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<title>Function template hash_value</title>
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<h2><span class="refentrytitle">Function template hash_value</span></h2>
<p>boost::hash_value — Provides hashing for <code class="computeroutput">variant</code> types so 
      that <code class="computeroutput">boost::hash</code> may compute hash.</p>
</div>
<h2 class="refsynopsisdiv-title">Synopsis</h2>
<div class="refsynopsisdiv"><pre class="synopsis"><span class="comment">// In header: &lt;<a class="link" href="../variant/reference.html#header.boost.variant.variant_hpp" title="Header &lt;boost/variant/variant.hpp&gt;">boost/variant/variant.hpp</a>&gt;

</span>
<span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> T1<span class="special">,</span> <span class="keyword">typename</span> T2<span class="special">,</span> <span class="special">...</span><span class="special">,</span> <span class="keyword">typename</span> TN<span class="special">&gt;</span> 
  <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">hash_value</span><span class="special">(</span><span class="keyword">const</span> <a class="link" href="variant.html" title="Class template variant">variant</a><span class="special">&lt;</span><span class="identifier">T1</span><span class="special">,</span> <span class="identifier">T2</span><span class="special">,</span> <span class="special">...</span><span class="special">,</span> <span class="identifier">TN</span><span class="special">&gt;</span> <span class="special">&amp;</span> rhs<span class="special">)</span><span class="special">;</span></pre></div>
<div class="refsect1">
<a name="id-1.3.44.5.5.6.4"></a><h2>Description</h2>
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<td><p><span class="term">Requires:</span></p></td>
<td>Every bounded type of the <code class="computeroutput">variant</code> must
          fulfill the requirements of the
          <a class="link" href="../variant/reference.html#variant.concepts.hashable" title="Hashable"><span class="emphasis"><em>Hashable</em></span></a>
          concept.</td>
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<td><p><span class="term">Effects:</span></p></td>
<td>Calls <code class="computeroutput">boost::hash&lt;T&gt;()(x)</code>, where <code class="computeroutput">x</code> is
          the content of <code class="computeroutput">rhs</code> and <code class="computeroutput">T</code> is its type.</td>
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<td><p><span class="term">Notes:</span></p></td>
<td>Actually, this function is defined in 
          <code class="computeroutput">&lt;boost/variant/detail/hash_variant.hpp&gt;</code> 
          header.</td>
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<div class="copyright-footer">Copyright © 2002, 2003 Eric Friedman, Itay Maman<br>Copyright © 2014-2024 Antony Polukhin<p>Distributed under the Boost Software License, Version 1.0.
    (See accompanying file <code class="filename">LICENSE_1_0.txt</code> or copy at 
    <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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